Discussion On Elastic Sling Breaking Of Overhead Contact Line In High Speed Railway And Countermeasures

Elastic sling is an important component of overhead contact line of high-speed railway,which can reduce the elastic inhomogeneity of each span overhead contact line and effectively improve the flow quality of pantograph.Therefore,a large number of high-speed railways use elastic sling,Wu-Guang high-speed railway is the first highspeed railway using elastic sling in China.In the 12 th year of operation of Wu-Guangzhou high-speed railway,a large number of elastic sling breaking problems appeared,which was also the first time in domestic high-speed railway.Therefore,the study on the reasons of elastic sling breaking has important reference significance for other high-speed railways.This paper is mainly based on the fatigue theory and the mechanical model of elastic sling.Firstly,the influence of the amplitude,length,tension and the position of the elastic sling on the elastic sling on the fatigue life of the elastic sling is analyzed theoretically.Then,field data are used to analyze the causes of elastic sling breakage from three aspects.First,statistical analysis of defects is carried out by using comparative analysis method and variance analysis method,and the rule that the longer the tunnel length,the more defects of elastic sling is obtained.In addition,insulation sampling data and 1C detection data are used to conclude that the contact force of arch net in the long tunnel is greater than that in the short tunnel.The conclusion that elastic sling is more likely to break the strand;Secondly,the parameters of the three typical defects are compared and analyzed,and the influence of the tension of the elastic sling and the position of the elastic sling on the elastic sling on the fatigue life of the elastic sling is verified,and the possible influence of the moment and levelness of the elastic sling clamp on the elastic sling is proposed.Thirdly,the parts of the elastic sling are inspected and analyzed,and it is verified that the broken strands of the elastic sling belong to fatigue failure,and the mechanical properties of the elastic sling meet the requirements of the design specifications.The fatigue source is the transverse crack formed by the extrusion of the anti-skid sawtooth between the elastic sling and the wire clip.Finally,according to the characteristics of the broken strands of the elastic sling such as concealment,rapid,high risk and difficult to deal with,as well as the fatigue factors of the elastic sling,the corresponding countermeasures are put forward: first,install a new wire clamp on the positioning side of the elastic sling;The second is to improve the 4C device,the image entry rate of the elastic sling and wire clip is increased to about 90%;The third is to reduce the sharpness of the non-slip sawtooth on the outside of the elastic sling wire clip and design the wire clip mouth as a bell mouth;The fourth is to improve the production process to overcome the problem of uneven surface organization,the use of stronger materials,the use of surface anticorrosion technology;Fifth,the elastic sling without adjustment installation technology and flexible use of 1C devices to adjust catenary parameters to the standard state;Sixth,the use of life and state combined management scheme.